Field of the Invention
This invention relates to video special effects apparatus and methods.
Description Of the Prior Art
U.S. Pat. No. 4,791,581 and United Kingdom Published Patent Application GB-A-2,254,751 describe examples of video special effects apparatus which transforms two-dimensional video images into pseudo three-dimensional video images in three-dimensional co-ordinate space.
In such conventional video special effects apparatus, one or more imaginary light sources can be used to generate an illusion of depth. However, such conventional video special effects apparatus has the disadvantage that it may generate inappropriate brighter portions in particular three-dimensional video images.
An example of such a situation is illustrated in FIG. 1 of the accompanying drawings. An imaginary light P is shone on to areas A and B of a free-form solid S. Since both area A and area B are facing the imaginary light P in a similar manner, the image intensity for both area A and area B is increased. However, in the real world, a shadow would be cast on area B by hump C. Thus, the increase in the image intensity For area B gives an unnatural appearance to the transformed image.
It is an object of the present invention to provide more realistic images in which such problems are reduced.